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(No Model.) 2 Sheets-Sheet 1.

0. J. LODGE. LIGHTNING ARRESTBR.

No. 429,727. Patented June 10, 1890.

FIG .4.

WPIJEEEES v UNITED STATES PATENT OFFICE.

OLIVER J. LODGE, OF LIVERPOOL, COUNTY OF LANCASTER, ENGLAND.

LlGHTNlNG-ARRESTER.

SPECIFICATION forming part of Letters Patent No. 429,727, dated June 10, 1890.

Application filed May 22 1889. Serial No. 311,676. (No model.)

To all whom it may concern.

Be it known that I, OLIVER J osnrn LODGE, D. Sc, F. R. S., a subject of the Queen of Great Britain, residing at Liverpool, in the county of Lancaster, in the Kingdom of Great Britain, have invented certain newand usefullmprovements in Lightning-Protectors, of which the following is a specification.

As the result of a long course of experiments on the conditions and phenomena of high-tension discharges, I have arrived at a method of reliably protecting any kind of apparatus from the effects of lightning or any other high-tension currents, however generated, which are not intended to enter it.

In the apparatus at present in use a short lead is brought from the linewire to an airv is already employed as a lightning -arrester,

or such as might easilybe employed. The shape of the opposing surfaces is immaterial, and the nature of the insulating substance between them is likewise optional. Thus by the term air-gap I intend to include a pair of knobs close together, or the space between the rounded ends of two rods, or between two plates, or between twopoin ts, or between a wire and a tube surrounding it, or any such already well-known plan. Similarly the insulating substance in the gap may be air, or it may be a thin film of mica or other solid insulator, as in the protectors used in the British Land Telegraph, as set forth in Figure 5, or it may be a partial vacuum, as in Varleys protectors. (Shown in Fig. 8.) In the instrument most used by cable companies the airgap is the space between a central thin wire and a point-carrying tube surrounding it, as set forth in Fig. 6. In telephoneprotectors it is the space between the teeth of two combs, as set forth in Fig. 7. In Varleys it is the space between two wires in a vacuumtube, as set forth in Fig. 8, and so on. I include under the word air-gap any of these already well-known lightnbig-protecting devices. I

My invention relates to the mode of connecting them up.

My invention consists in the use of a number of such air gaps connected to each other by coils of wire or ribbon, which oppose the current rather by self induction or electro magnetic inertia than by resistance proper. The line current has to go past all of the air-gaps, while the momentary hightensional currents are shunted through the gaps. The gaps are of either adjustable or fixed width, and the line current has to go past all of the air-gaps, while the momentary high-tensional currents are shunted through the gaps. The apparatus to be protected, Whether it be lamps, or inside wires,or underground or submarine cables, telephones, telegraphic instruments, galvanometers, meters, or any other kind of electrical apparatus, is connected to the last airgap of the series. The line-wire, or exposed leads, or other wires into which it is feared thatlightning or hightension currents may possibly come, are connected to the first air-gap of the series.

Referring to the drawings, Fig. 1 shows a simple form of carrying my invention into elfect with adjustable air-gaps; Fig. 2,a simple arrangement for lightning-switch, specially useful at the j unction of overhead an d under ground or submarine lines, or other position where there are covered wires or cables to protect; Fig. 3, an arrangement useful at an intermediate telegraph station having no earth-connection. Fig. l shows the invention utilizing existing lightnlug-protectors, such as plates or tubular protectors. Figs. 5, 6, 7, and S are detail views of well-known devices for shunting currents of more than desired strength.

Like letters refer to like parts in all the drawings.

Referring first to Fig. 1, A and 13 are the terminals inserted in the leads, or A is connected with the line-wire and B with earth.

O D are terminals connected with the instrument to be protected, or G with the instrument and D with the earth, or C with the instrument and D left insulated, as desired.

E E 850., represent air-gaps.

G G, &c., are self-induction coils, consist ing, forinstance, of gutta-percha-covered wire coiled upon bobbins.

The action of the arrangement is as follows: The ordinary currents which it is intended to transmit through the apparatus to be protected traverse the self-induction coils G G, &c., and do not j nmp any of the air-gaps; but lightning or any other foreign and violent currents which may accidentally have got into the leads will jump one or more of the series of air-gaps, and be thus diverted from the instruments or lamps to be protected. Thus the insulating-spaces or airgaps may be arranged so that the greater portion of a violent discharge will jump the first II; a certain fractionsay a tenthof the remainder will jump the second E another fraction-say a tenth of this again-will jump the third E, and so on, the amount finally permitted to go through the protected instrument being thus reduced to any desired amount.

It may be well to set the air-gaps or insulating-spaces of different widthsforinstance, the first having broad rounded ends wider apart than the second, exposing larger surface and capable of easy examination and replacement, as by bindingscrew 7b, in case of damage by a flash; the second small rounded ends or points close together and capable of minute adjustment by screwing up, as shown, with lock-nuts or equivalent device; the third still closer and finer, (to. It may also be well to vary the connecting-coils, using thicker and more highly-insulated wire for the earlier coils and thinner for the later, as shown.

Fig. 2 shows a variation useful for protecting the insulation of covered wires or cables in which the exposed line is attached to terminal A and the protected one to C. 13 is connected to earth.

The first F is preferably a knob, plate, or rounded end, as shown, and of stout conducting material. The second and subsequent ones F F, &c., can be knobs or points, preferably the latter, and can be adjusted nearer the central knob F than 11" is.

In place of self-induction coils I may use straight wires, carbon rods, mercury-tubes, or other conducting arrangement giving sufficient impedance or resistance, can be used; also each of the knobs or points F F F F can be connected directly with the earth instead of with each other.

In Fig. 3, A is connected to the up-line wire, B to the down-line wire, 0 and D to all the instruments in the station, and K to the earth. The conductor K, connected with the earth, is placed between the entrance and exit wires, each of which is provided, (with a series of knobs, plates, or points with self-induction coils between,) forming airgaps with this conductor.

I am aware that it has been proposed heretofore to protect a dynamo-machine or other in stru mcnt from abnormally-high-tension currents by placing a self-induction coil on the main-line circuit between the safety-branch or broken ground-connection and the machine to be protected, and I do not broadly claim this as my invention.

I claim as my invention 1. As a lightning-protector, a series of two or more air-gaps arranged one after the other on the line-circuit with self-induction coils be tween, whereby the greater portion of the high-tension elcctricityis shunted at the first gap, the greater portion of the remainder at the second, and so on.

2. A series of two or more knobs or their equivalents, each independently electrically connected with the line-wire or lead,but having self-induction coils between them in the line-wire, and one or more conducting-surfaces in communication with the earth placed in juxtaposition, but not actually touching the first-mentioned set, substantially as and for the purposes described.

3. The combination of a series of insulat ing-spaces or air-gaps with self-induction coils between, of a series of independent adjustable devices, whereby the width of gap can be regulated.

at. In a protector against lightning or hightension electricity formed of a series of airgaps, as described, with self-induction coils between, a first gap of very stout proportions and discharging capacity, and succeeding ones of smaller proportions and capacity, whereby each part is proportioned to the work it has to do.

5. In a lightning or high-tension-current protector, a series of air-gaps with selt-induc tion coils between them, said gaps being successively narrower, substantially as described.

6. In a protector against lightning or hightension electricity formed of a series of airgaps with self-induction coils between, the arrangement of a first gap with large opposing surfaces, and the latter gaps with smaller opposing surfaces, whereby the bulk of the hightension electricity can pass with less injury to the apparatus and the residue with more case owing to the conductors being pointed.

7. The combination, with existing protecting devices, of one or more additional airgaps wit-h self-induction coils between each of said 1ightning-protecting devices or airgaps and thenext, whereby the residual hightension electricity that would pass the existing lightning-protccting devices is eliminated, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

OLIVER J. LODGE.

Witnesses:

W. P. THOMPSON, II. P. SHOOBRIDGE. 

